Flow Data Format

Cybersecurity engines, QoE managers, performance analytics solutions, and other third-party applications can connect to the Netify DPI Agent to interact with the network flow metadata. The Netify Agent's socket interface (TCP/IP and UNIX sockets) provides near real-time agent status and flow/DPI detection data via JSON encoded payloads.

With the Netify DPI Data Stream, you can develop and create your own integrations: open source, proprietary, in-house... it's up to you.

Application: WhatsApp

The detected_application_name shows that it was a flow generated by WhatsApp. In this particular case, this detection was made using the TLS/SSL SNI hostname and certificate common name. Other heuristics are also used to detect applications.

Protocol: HTTPS

The DPI engine detected the HTTPS protocol (detected_protocol). This is more than just mapping port 443 to HTTPS, the engine did a full deep packet inspection and used the Application-Layer Protocol Negotiation (ALPN) data to fine-tune detections. In fact, Netify will detect SSL/SNI over any port.

Category

The application, domain and protocol categories are given in the flow data. In this example, the application category is "Messaging" (#17) and the protocol category is "Web" (#22).

Risks

Any flows that trigger a risk event will have details provided in the risk section of the metadata.

Other/Local Nomenclature

The local designation indicates the endpoint's local side, and the other designation will be indicated by the other_type field. These designations do not indicate a flow's direction. To determine which side of a flow started the conversation, consult the local_origin field. When this field is true, it indicates that the local endpoint started transmitting first. When false, the opposite endpoint started the flow.

In the stats data (see below) and referencing the example to the right, we see:

"local_origin": true
"local_ip": "192.168.4.105",
"local_bytes": 2434,
"other_type": "remote",
"other_ip": "31.13.80.53",
"other_bytes": 6139

In this example, 192.168.4.105 transmitted 2434 bytes and received 6139 bytes from 31.13.80.53. The flow originated from 192.168.4.105.

DPI: HTTPS Details

Detecting the protocol is just the start. The Netify Agent also breaks down the details of the SSL/TLS connection:

• SNI hostname: static.whatsapp.net
• Certificate CN: *.whatsapp.net
• TLS version: 0x0303 (TLS 1.2)
• Encryption cipher: 0xc02b info
• JA3/TLS fingerprint: details
• Subject DN

Other protocols will have different metadata attached. For example, HTTP traffic also includes the URL and user agent.

{
  "type": "flow",
  "interface": "ens34",
  "internal": true,
  "established": false,
  "flow": {
    "category": {
      "application": 17,
      "domain": 0,
      "protocol": 22
    },
    "risks": {
      "ndpi_risk_score": 10,
      "ndpi_risk_score_client": 5,
      "ndpi_risk_score_server": 5,
      "risks": [ 15 ]
    },
    "digest": "09c9e2b73d68fef245c09141cb63dad8d9001a6c",
    "ip_nat": false,
    "ip_version": 4,
    "ip_protocol": 6,
    "vlan_id": 0,
    "other_type": "remote",
    "local_origin": true,
    "other_mac": "00:90:fb:29:ca:ba",
    "local_mac": "a0:c9:a0:e5:2c:eb",
    "other_ip": "31.13.80.53",
    "local_ip": "192.168.4.105",
    "other_port": 443,
    "local_port": 38972,
    "detected_protocol": 196,
    "detected_protocol_name": "HTTPS",
    "detected_application": 544,
    "detected_application_name": "142.netify.whatsapp",
    "detection_guessed": 0,
    "ssl": {
      "alpn": [
        "h2",
        "http/1.1"
      ],
      "alpn_server": [],
      "version": "0x0303",
      "cipher_suite": "0xc02b",
      "client_sni": "static.whatsapp.net",
      "server_cn": "*.whatsapp.net",
      "client_ja3": "d8c87b9bfde38897979e41242626c2f3",
      "server_ja3": "6e15a5bf660856fa03186247ca41d059",
      "issuer_dn": "C=US, O=DigiCert Inc, OU=www...",
      "subject_dn": "C=US, ST=California, L=Menlo..."
    },
    "first_seen_at": 1574786068665,
    "first_update_at": 1574786068665,
    "last_seen_at": 1574786068715
  }
}

Description

When a network flow is either closed or becomes idle, the Netify Agent publishes a flow_purge record to the Data Stream. Today, this stream provides network statistics: byte counters, traffic counters, timestamps, etc. In the near future, expect to see performance information added to the payload, for example:

• Statistics on DNS response times
• HTTP response codes and times
• Network performance statistics
• and more

"type": "flow_purge"
"reason": "expired",
"flow": {
  "digest": "178bf5650a79d5e8ddc6a988d0c02b3d799180d0",
  "last_seen_at": 1606232131756,
  "local_bytes": 2434,
  "local_packets": 21,
  "other_bytes": 6139,
  "other_packets": 16,
  "total_bytes": 8573,
  "total_packets": 37,
  "detection_packets": 3,
  ... snip ...

Description

Some network flows are long-lived, for example, audio/video streams and VPN connections. The Netify Agent will periodically publish a flow_stats record to the Data Stream. The network status on active flows provides real-time insights into the network.

Example Use Cases

• Live bandwidth statistics
• QoE based on live data usage

"type": "flow_stats",
"flow": {
  "digest": "178bf5650a79d5e8ddc6a988d0c02b3d799180d0",
  "last_seen_at": 1606232131756,
  "local_bytes": 2434,
  "local_packets": 21,
  "other_bytes": 6139,
  "other_packets": 16,
  "total_bytes": 8573,
  "total_packets": 37
},

The interfaces data type provides the MAC address and associated IPs for the given network interface.

"type": "interfaces",
"eth0": {
  "mac": "02:42:ac:11:00:02",
  "role": "LAN"
  "capture_type": "PCAP",
  "addr": [
    "fe80::42:acff:fe11:2",
    "fd20:c0:ca67::242:ac11:2",
    "172.17.0.2"
  ],
}

The interface_stats data type provides various statistics on the performance of the underlying network interface.

"type": "interface_stats",
"eth0": {
  "capture_dropped": 0,
  "capture_filtered": 0,
  "discarded": 0,
  "discarded_bytes": 0,
  "ethernet": 7,
  "flow_dropped": 0,
  "fragmented": 0,
  "icmp": 0,
  "igmp": 0,
  "ip": 7,
  "ip_bytes": 918,
  "largest_bytes": 215,
  "mpls": 0,
  "pppoe": 0,
  "queue_dropped": 0,
  "raw": 7,
  "tcp": 0,
  "tcp_resets": 0,
  "tcp_seq_errors": 0,
  "udp": 7,
  "vlan": 0,
  "wire_bytes": 1086
},

The endpoints data type provides the MAC address and associated IPs for detected systems on the network.

"type": "endpoints",
"02:42:3f:e6:a4:ee": [
  "172.17.0.1"
],

The agent_hello data type provides versioning and feature information. This makes it possible for third-party applications to manage upgrades and changes to the Netify Agent data stream.

"type": "agent_hello",
"agent_version": 5.0.1,
"build_version": "Netify Agent/5.0.1 (debian; x86_64; ...)",
"json_version": 1.9

The agent_status data type provides agent information, including memory usage, cache sizes and more.

"type": "agent_status",
"cpu_cores": 8,
"cpu_system": 0.157047,
"cpu_system_prev": 0.151123,
"cpu_user": 0.088339,
"cpu_user_prev": 0.086594,
"dhc_size": 0,
"dhc_status": true,
"flow_count": 7,
"flow_count_prev": 7,
"flows_active": 1,
"flows_expired": 0,
"flows_expiring": 0,
"flows_in_use": 1,
"flows_purged": 0,
"maxrss_kb": 28324,
"maxrss_kb_prev": 28324,
"tcm_kb": 9077,
"tcm_kb_prev": 9100,
"timestamp": 1697557964,
"update_imf": 1,
"update_interval": 15,
"uptime": 450